Catches are woven into nearly every contract the Fae make with the other powers of the cosmos. Most contracts were originally crafted by the True Fae, and changelings get to use them by “signing on” to the relevant clauses. When invoked by a changeling, a clause’s catch absolves the changeling of any glamour cost, but they must still pay any listed Willpower cost to activate the clause.
Court contracts, on the other hand, were never touched by Gentry. Their catches negate all costs, including Willpower, when invoked by a changeling.